The subject matter disclosed herein relates to an improved integrated gasification combined cycle (IGCC) power plant.
An integrated gasification combined cycle (IGCC) power generating plant performs a two-stage combustion with cleanup between stages. The first stage includes a gasifier for partial oxidation of a fossil fuel, such as coal or heavy fuel oil, and the second stage utilizes a gas turbine combustor for burning the fuel gas produced by the gasifer. Performance of the gas turbine combustor is enhanced by the addition of compressed diluent nitrogen. Diluent nitrogen from an air separation unit (ASU) in the IGCC is compressed in stages by a diluent nitrogen compressor (DGAN) and inter-cooled between stages by a cooling tower water source. The compressed nitrogen is then supplied to the gas turbine combustor. The DGAN compressor consumes power as an auxiliary load. The DGAN compressor may consume a large amount of power, lowering the overall efficiency of the IGCC power plant.
Accordingly, there remains a need in the art for a reduction in the power load consumed by a DGAN compressor operated in conjunction with an IGCC power plant.